Call me a cynic, but I cannot believe in the dynamic nature of humans. Change arrives at a snail's pace and specific changes must be deliberate decisions actively worked at over time.
At the beginning of a relationship—or even down the road—people are on their best behavior, making any sign of disrespect at all should be given the utmost consideration. From what I've seen the baseline for any sort of healthy relationship should surely include respect and honesty. Whether someone treats you with respect has more to do with them than with you—remember that if you become entangled with a disrespectful man.
IT'S. NOT. YOU. It's them. It's not your responsibility to even attempt to change them. Do not even try—trust me, I've been there and it gets you absolutely nowhere. These sorts of people tend to be too stubborn to even admit they have a problem, and if they did, wouldn't care enough about other people to fix it. My best advice to you if you suspect you're with a disrespectful partner (or are starting to become involved with one) is to run in the other direction as fast as you can.
1. Crosses your boundaries (or pushes you to loosen them)
You will let him know what's okay and not okay, and he may seem to accept it at the moment, but it'll gnaw at him—he may bring it up and try to persuade you in the other direction. A man who really respects you will in turn respect your boundaries or whatever decisions you've made for yourself. Your comfort and limits you've set for yourself matter much, much more to him than anything else.
2. Uses the phrases "not to sound like a dick" or "I know this makes me sound like an asshole"
Maybe you're saying these things because you ARE a dick or an asshole? Ever think of that??
Assholes are assholes and dicks are dicks because they seem that way to other people, it's not really up to an individual to label themselves as NOT. It's up to the people around them and how he makes them feel. I cannot tell you how many times a man has played the card "I know this makes me seem like a dick, but I'm definitely not a dick even if I act like a dick in every sense of the word." Not those exact words, but yeah, you get it.
3. Holds onto the label "nice guy" or "honest guy" for dear life
In general, people cannot self-evaluate with any reliable degree of accuracy—the labels people hold onto are what they want you to see and think, and you shouldn't necessarily trust them. These descriptors, "nice guy" or "honest guy" tell you how to expect to be treated, but don't tell you much about who the person actually is. From my experience, the worst people described themselves as "nice guys" and the most dishonest as "honest guys," so I've learned that the opposite is often far closer to the truth.
4. Doesn't demonstrate respect for what's important to you—or worse, demonstrates disrespect
I've told men that I'm a writer and an aspiring therapist and could tell right then and there whether I would make it past that singular conversation with them. I've received comments like "hahahahah I hate writing" or "that's actually really sad" or no acknowledgement that I said anything at all as he proceeded to talk about himself—all of these responses were highly disrespectful. What you do or aspire to do is a huge part of who you are, and for him to not pay his respects is a form of disrespect towards you.
5. He's flaky as hell and shows up only when it's convenient
You have to go the extra mile to ensure he doesn't flake—or to get him somewhere at all as you two planned. He may reschedule constantly if he reschedules at all or keeps pushing back your meeting time to later in the day. Or he may show up out of the blue when he feels like it.
6. Leaves you in the dark about what he really wants or about his life
You'll go on and on about the minute details of your life, what's going on with your friends, what you want in the future, where you'd want this relationship to go, but you have absolutely no idea about what's going on with him. You may be given general details about his life, whether that means a big project with work or being particularly busy, but when it comes to the things that really matter you're left in the dark.
7. Leaves you on "read" but demands to know why you haven't responded within a few hours
He can leave you on read and not respond for days, but when he finally responds, he'll demand to know what's up if you don't respond in a heartbeat. In other words, he wants you to be at his beck and call, but doesn't express that you deserve to hear back in a reasonable amount of time. This extends to any number of circumstances—he expects all of your attention and care, but delivers barely a sliver to you in return.
8. Uses guilt-trapping or other emotionally manipulative methods to get his way
It doesn't matter what you say, he wants to do what he wants to do and he'll do whatever it takes to persuade you. He'll make you feel like you're being stupid, he'll make you feel like your decisions are foolish, he'll make you feel guilty and responsible for his emotions. Doesn't matter what's important to you because what's important to him somehow matters more.
9. You get the feeling he could drop you at a moment's notice
He hasn't expressed that he cares enough about you to fight for you during the rough patches or stressful periods that we all face; in fact, it seems like he tries to avoid all sense of emotional attachment in order to keep his power over you. He doesn't respect you enough to go all in or all out, there's always a sense that he could jump ship when the tides start to turn.
10. You don't FEEL respected
Ultimately, this is one of the most important determinants. Doesn't matter if he supposedly has all the respect for you in the world if you can't feel it. There's a difference between a lack of respect and blatant disrespect, yet neither make for a healthy relationship. You should feel that not only does he have a deep respect for those he meets in general, but that he has a particularly strong sense of respect towards you.
Take a man's words with a grain of salt, until he's gained your hard-earned trust and demonstrated the power of his word. Instead, pay extreme attention to what his actions are telling you. You don't want someone who doesn't respect you because once you stay with him, you stop respecting yourself and that is the most damaging effect of all. Take care of yourself and hold out for the partner that respects you 100%.